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Area forecast discussion 
National Weather Service Taunton Massachusetts
1000 am EDT Friday Sep 4 2015

Canadian high pressure builds into New England today...bringing a
brief end to the recent warm and humid weather. The high will
provide the region with mild days and cool nights through Saturday.
As the high shifts south of New England Sunday a warming trend
develops with temperatures becoming much warmer than normal along
with increasing humidity Monday through Wednesday. Dry weather
continues until late next week when a cold front may yield the risk
for scattered showers and T-storms.


Near term /until 7 PM this evening/...
10 am update...
backdoor front has moved to the S with NE flow ushering in cooler
and drier air. Dewpoints have fallen into the 50s across much of
southern New England. Gusty NE winds will gradually subside from north to S this
afternoon as the ridge builds southward into southern New England but gusty winds will
persist along the South Coast through much of the afternoon.

Models indicating drying morning in from the NE but there is
shallow low level moisture developing across southeast Massachusetts this
afternoon. So while increasing sunshine is expected in east new eng
may see some shallow SC developing across southeast Massachusetts. Also expect
developing SC in west new eng where moisture is more robust.

Soundings show shallow mixing only to 950 mb in the east and 900
mb in the west. Expect temperatures holding around 70 degrees in east
coastal Massachusetts due to NE flow with maxes near 80 in the CT
valley...and 70s elsewhere.


Short term /7 PM this evening through 6 PM Saturday/...
high pressure will slide from the NE behind exiting backdoor front.
Mass fields all suggest rapid slackening. This weak pressure gradient
combined with clear skies suggest good setup for radiational
cooling. With cool middle level temperatures and highs today below
normal...expect lows to dip into the low 50s in normal radiational
spots. Not out of the question...deeper valleys of northwest Massachusetts may
approach the upper 40s. A the windows kind of

another dry day with high pressure. Clear skies and some onshore
flow continues. However slight warming aloft and winds shifting
somewhat expect highs mainly near normal. In the middle 70s /near
shore/ to low 80s interior.


Long term /Saturday night through Thursday/...

* warmer than normal temperatures return sun and into most of next week
* dry weather continues into at least the middle of next week

Synoptic overview and guidance evaluation...

04/00z gefs and ecens ensembles along with deterministic guidance
are trending toward the subtropical ridge lingering longer along the
East Coast next week. This suggest warmer than normal temperatures arriving
Sunday will persist much of next week along with increasing
humidity. Heat and humidity may not break until next Thursday or Friday as
northern stream energy finally ejects southeast into New England and
erodes the northern periphery of the ridge.

Sat night/Sunday...

Not as cool as Friday night but still seasonable cool along with
comfortable humidity. Then Sunday airmass gradual warms but with
ridge axis over the area humidity remains in check with dew points only
climbing into the mu50s. Highs should climb into the low to middle 80s
inland...70s at the shore in response to cooling afternoon

Monday through Wednesday...

Ridge axis shifts south of New England allowing anomalous heat to
advect into New England with 850 mb temperatures climbing to +18c Tuesday and Wednesday.
This warmth aloft combined with west-southwest surface winds will support highs
85 to 90. Humidity increases too with dew points rising into the 60s
Tuesday and Wednesday.


As mentioned above ensembles and deterministic guidance have slowed
the arrival of next frontal passage to next Thursday or Friday. Thus next
chance for showers/T-storms not until late next week.


Aviation /14z Friday through Tuesday/...
forecaster confidence levels...

Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.

Short term /through Friday night/...high confidence.

10 am update...
patchy MVFR ceilings along the S coast and west new eng will improve to
VFR with clearing moving in from the NE. May see some patchy MVFR
ceilings developing this afternoon across southeast Massachusetts bur low confidence.
NE winds diminishing from north to S but still gusts 20-25 knots near S
coast and cape/islands into the afternoon.

Tonight... VFR. Some isolated fog mainly in western valleys late

mainly VFR.

Kbos terminal...high confidence in trends.

Kbdl terminal...high confidence in taf.

Outlook /Saturday night through Tuesday/...high confidence.

VFR through the period. Areas of early morning IFR ceilings/visibilities
possible in fog. Light flow with sea breezes possible Sunday.
Increasing west-southwest flow Monday-Tuesday.


forecaster confidence levels...

Low...less than 30 percent.
Moderate...30 to 60 percent.
High...greater than 60 percent.

Short term /through Friday night/...high confidence.

Today into tonight...
with strong high pressure moving in from the NE...N-NE flow will
increase to around 25 knots over the waters through the
morning...shifting to the southern waters by middle day. This will also
allow seas to reach 4-5 feet. Small Craft Advisory timing/placement
currently look good so no proposed changes. Conditions subside

high pressure will lead to quiet weather across the waters.

Outlook /Saturday night through Tuesday/...high confidence.

Tranquil boating weather this period as a large high pressure
remains over...or near...the waters. Mainly light and variable
winds with local sea breezes way to a more
sustained south to southwest flow early next week.


Box watches/warnings/advisories...
Rhode Island...none.
Marine...Small Craft Advisory until 8 PM EDT this evening for
Small Craft Advisory until noon EDT today for anz230-236.
Small Craft Advisory until 6 PM EDT this evening for anz250-
Small Craft Advisory until 2 am EDT Saturday for anz254>256.


near term...kjc
short term...doody
long term...nocera

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